Polio can be circulating through a community long before anyone is paralyzed. Monitoring sewage for the virus lets public health officials short-circuit this 'silent transmission.'

In this April 14, 1947 file photo, a long line winds toward the entrance to Morrisania Hospital in the Bronx borough of New York, where doctors were vaccinating against smallpox. In an attempt to halt the spread of the disease, officials said city residents were being vaccinated at the rate of eight a minute.
(AP Photo/File)Oktober 3, 2018

Vaccines have long been considered safe, but many people still believe they are not. A new study shows that people who think they know more than medical experts are more likely to believe that vaccine are not safe.

To reduce the incidence of hepatitis B in Canada and to reduce mother-to-child transmission, it is vital that we vaccinate all infants at birth.
(Shutterstock)Juni 15, 2018

Stating a majority of people won't benefit from a vaccine ignores the purpose of immunisation programs.

A vaccine (toxoid) against diphtheria first became available in Toronto in 1926. Thanks to the work of the Toronto Diphtheria Committee, the city was diphtheria-free by 1940.
(Shutterstock)Mei 31, 2018